Move all Dropbox data to Google Drive? (Without reuploading)

You may also find zapier.com and IFTTT.com may be able to help you, they have links to both services so you may be able to build a "recipe" that will do what you want.

 

The problem is that "Cloud" storage relies heavily on a fast and reliable Internet connection. Therefore, the only way to possibly achieve this is to completely "trust" a third party service to move your data directly between the services. The problem with this is that you cannot trust any such service to do so without wanting something in return. In most cases, they will in some way want to mine your data so I would avoid this altogether.

Your best bet (although still possibly insecure) would be to take your computer to a different location that does have ast Internet (a public library for example) and then use their Internet connection to move your files from your DropBox to Google Drive folders.

 

MultCloud is another option (notice no "i").